1. Field of the Disclosure
This application relates generally to methods and apparatuses for performing minimally invasive surgery, and more particularly to methods and apparatuses for performing procedures for stabilizing adjacent bones while preserving motion therebetween.
2. Description of the Related Art
In the past, patients suffering from degenerative spine conditions, such as progressive degeneration of intervertebral discs, have been treated by various techniques. For example, fixation and fusion are two procedures that are sometimes performed in combination to address degeneration of the intervertebral discs. Fusion involves the replacement of an intervertebral disc with a bone graft intended to fuse the adjacent vertebrae together. Fixation provides an external structure that bridges from one vertebra to an adjacent vertebra to eliminate motion therebetween. While fusion and fixation may reduce some symptoms of disc degeneration, the elimination of motion reduces the patient's flexibility and may cause other complications.
Also, these procedures are typically performed by way of open spine surgery. In open spine surgery, the surgeon typically makes large incisions and cuts or strips muscle tissue surrounding the spine to provide open access to the troubled area. This technique exposes nerves in the open area, which can be injured when exposed. Consequently, open surgery carries significant risks of scarring, pain, nerve damage, and blood loss. Open surgery also subjects patients to extended recovery times.
Less invasive techniques have been proposed to reduce the trauma of open spine surgery. For example, a constant diameter cannula has been proposed to reduce incision length associated with open surgery. Unfortunately, such cannulae are usually very narrow and therefore they provide minimal space for the physician to observe the body structures and manipulate surgical instruments.